> What I want to do is to find graph anti-isomorphisms. By
> anti-isomorphic I mean a graph which is isomorphic to a (proper) edge
> induced subgraph of the graph complement of another graph (of course
> provided that the graphs are not complete).
>
> How would the igraph.isomorphic functions (under the BLISS or the VF2
> algorithms) work in this case?
Theoretically this could be done by creating the adjacency list of the
complement graph of one of the graphs in igraph_subisomorphic_function_vf2
and working with that. There is no way to do it from R or Python directly
without messing around with the C source -- of course excluding the
possibility of actually generating the complement graph. Chances are that
the memory requirements would be huge for even moderately large graphs (with
a few thousand nodes) since most graphs that igraph users work with are
sparse, hence their complement is very dense.
If your graphs are small, I advise you to simply generate the complement
graph for graph2 explicitly and run the subisomorphism function on graph1
and the complement of graph2.
Best,
Tamas